Germs. Dr. Donald Redelmeier is a clinical epidemiologist at the University of Toronto. And he says elevator buttons are 50%dirtier than public toilet flushers and bathroom door handles. So what can you do if you can’tfind the stairs – or you’re in a hurry – or you’re on crutches? Use your elbow to press the buttons – or a pencil eraser.

While it’s true that the more people we’re around – the moreinfections we’re exposed to, that’s actually a good thing. It strengthens our immunity over time. And the British Medical Journal found that extroverts, who spent a lot of time with others, had heartier immune systems and were more resilient when they did get sick, thanloners. Anotherupside of being social? Researchers think that spending time with other people stimulates certain genes that help the body fight off viruses.